/* ========================================================================
 * Bootstrap: affix.js v3.3.5
 * http://getbootstrap.com/javascript/#affix
 * ========================================================================
 * Copyright 2011-2015 Twitter, Inc.
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * ======================================================================== */

/**
 * Customized by Ivan.Nginx
 *
 * - Refactored with eslint-config-theme-next style.
 */

(function($) {
  'use strict';

  // AFFIX CLASS DEFINITION
  // ======================

  var Affix = function(element, options) {
    this.options = $.extend({}, Affix.DEFAULTS, options);

    this.$target = $(this.options.target)
      .on('scroll.bs.affix.data-api', $.proxy(this.checkPosition, this))
      .on('click.bs.affix.data-api',  $.proxy(this.checkPositionWithEventLoop, this));

    this.$element     = $(element);
    this.affixed      = null;
    this.unpin        = null;
    this.pinnedOffset = null;

    this.checkPosition();
  };

  Affix.VERSION  = '3.3.5';

  Affix.RESET    = 'affix affix-top affix-bottom';

  Affix.DEFAULTS = {
    offset: 0,
    target: window
  };

  Affix.prototype.getState = function(scrollHeight, height, offsetTop, offsetBottom) {
    var scrollTop    = this.$target.scrollTop();
    var position     = this.$element.offset();
    var targetHeight = this.$target.height();

    if (offsetTop != null && this.affixed === 'top') return scrollTop < offsetTop ? 'top' : false;

    if (this.affixed === 'bottom') {
      if (offsetTop != null) return scrollTop + this.unpin <= position.top ? false : 'bottom';
      return scrollTop + targetHeight <= scrollHeight - offsetBottom ? false : 'bottom';
    }

    var initializing   = this.affixed == null;
    var colliderTop    = initializing ? scrollTop : position.top;
    var colliderHeight = initializing ? targetHeight : height;

    if (offsetTop != null && scrollTop <= offsetTop) return 'top';
    if (offsetBottom != null && (colliderTop + colliderHeight >= scrollHeight - offsetBottom)) return 'bottom';

    return false;
  };

  Affix.prototype.getPinnedOffset = function() {
    if (this.pinnedOffset) return this.pinnedOffset;
    this.$element.removeClass(Affix.RESET).addClass('affix');
    var scrollTop = this.$target.scrollTop();
    var position  = this.$element.offset();
    return (this.pinnedOffset = position.top - scrollTop);
  };

  Affix.prototype.checkPositionWithEventLoop = function() {
    setTimeout($.proxy(this.checkPosition, this), 1);
  };

  Affix.prototype.checkPosition = function() {
    if (!this.$element.is(':visible')) return;

    var height       = this.$element.height();
    var offset       = this.options.offset;
    var offsetTop    = offset.top;
    var offsetBottom = offset.bottom;
    var scrollHeight = Math.max($(document).height(), $(document.body).height());

    /* eslint-disable */
    if (typeof offset !== 'object')         offsetBottom = offsetTop = offset;
    if (typeof offsetTop === 'function')    offsetTop    = offset.top(this.$element);
    if (typeof offsetBottom === 'function') offsetBottom = offset.bottom(this.$element);
    /* eslint-enable */

    var affix = this.getState(scrollHeight, height, offsetTop, offsetBottom);

    if (this.affixed !== affix) {
      if (this.unpin != null) this.$element.css('top', '');

      var affixType = 'affix' + (affix ? '-' + affix : '');
      var e         = new $.Event(affixType + '.bs.affix');

      this.$element.trigger(e);

      if (e.isDefaultPrevented()) return;

      this.affixed = affix;
      this.unpin = affix === 'bottom' ? this.getPinnedOffset() : null;

      this.$element
        .removeClass(Affix.RESET)
        .addClass(affixType)
        .trigger(affixType.replace('affix', 'affixed') + '.bs.affix');
    }

    if (affix === 'bottom') {
      this.$element.offset({
        top: scrollHeight - height - offsetBottom
      });
    }
  };

  // AFFIX PLUGIN DEFINITION
  // =======================

  function Plugin(option) {
    return this.each(function() {
      var $this   = $(this);
      var data    = $this.data('bs.affix');
      var options = typeof option === 'object' && option;

      if (!data) $this.data('bs.affix', data = new Affix(this, options));
      if (typeof option === 'string') data[option]();
    });
  }

  var old = $.fn.affix;

  $.fn.affix             = Plugin;
  $.fn.affix.Constructor = Affix;

  // AFFIX NO CONFLICT
  // =================

  $.fn.affix.noConflict = function() {
    $.fn.affix = old;
    return this;
  };

  // AFFIX DATA-API
  // ==============

  $(window).on('load', function() {
    $('[data-spy="affix"]').each(function() {
      var $spy = $(this);
      var data = $spy.data();

      data.offset = data.offset || {};

      /* eslint-disable */
      if (data.offsetBottom != null) data.offset.bottom = data.offsetBottom;
      if (data.offsetTop    != null) data.offset.top    = data.offsetTop;
      /* eslint-enable */

      Plugin.call($spy, data);
    });
  });

}(jQuery));
